Fig. 4

Dictyostatin treatment increased MT density in optic nerves of aged PS19 mice. MTs were counted in electron micrographs (50,000X) of cross-sections of optic nerves (a bar = 0.5 μm) from dictyostatin- or vehicle-treated aged PS19, or vehicle-treated WT mice, as previously described [46]. b An expanded imaged showing the grid of hexagons applied to optic nerve EM images (bar = 0.1 μm). To avoid repeat counting, only MTs that resided within the hexagon or were on one of the three indicated borders of each hexagon were counted. MTs are identified by arrows. c Quantification of MTs/area in the optic nerves of mice from each treatment group. Error bars denote SEM, with group sizes of 8–11. **, p < 0.01 as determined by one-way ANOVA with a post-hoc Tukey’s multiple comparison test